Intermittent drive mechanism



May 1969 J. R. PELTZ ETAL 3,446,036

INTERMITTENT DRIVE MECHANI SM Filed June 5, 1967 United States Patent US. Cl. 74-112 Claims ABSTRACT OF THE DISCLOSURE A drive mechanism to impart intermittent motion to a driven member from a rotating drive shaft. The driven member having a driving surface is disposed adjacent the drive shaft such that the driving surface normally contacts the drive shaft.

The driving surface includes one or more detents formed to prevent contact between the driving surface and the drive shaft when a detent is adjacent to the drive shaft. A drive tip is mounted loosely and concentrically on the rotating drive shaft and is held stationary by an escapement device. When the escapement device releases the drive tip, the drive shaft turns the drive tip into the detent of the driven member and by means of a wedging action imparts motion to the driven member to bring the driving surface of the driven member into contact with the rotating shaft.

Background of the invention This invention relates generally to drive mechanisms, and more particularly to improved intermittent drive mechanisms.

Numerous intermittent drive mechanisms are known in the art, for example, to provide periodically recurring drive motion or to provide a desired drive motion upon command or the occurrence of a predetermined event. Typical of the former type is the so-called Geneva wheel has found widespread application in the mechanical art. However, this general type of mechanism is restricted to use where the intermittent drive motion is required on a regularly recurring basis with equally spaced intervals between each intermittent drive period. To provide intermittent drive motion on an irregular basis and for varying period of driving time, it is common practice to utilize driving means activated by an electrical or mechanical switch or a combination of the two. For example, a solenoid driven ratchet or cam may be used to provide the desired drive motion or a solenoid alone may be used to provide the driving force. In other cases slip gears with special clutching means may be used to couple driving energy intermittently from a continuously moving member.

Generally, the mechanical means for providing the intermittent drive require a considerable amount of power to initiate the drive motion. In addition such mechanisms are often comparatively expensive and may produce undesired noise. The solenoid powered drive means require a relatively large current which produces an inherent inductive surge each time the solenoid is activated. The inductive surge produces an electrical noise which appears as a pop in the audio system and is difiicult to filter out. Also, the solenoids, as well as some of the mechanical mechanisms, are quite bulky and therefore not easily adapted for use in smaller systems.

The prior art mechanisms and the problems encountered therewith have been particularly annoying in devices such as automatic record changers and tape cartridge players. In such systems, the need for the intermittent driving forces are determined by the size of the 3,446,086 Patented May 27, 1969 record or the length of the recording tape which may vary over a considerable range and therefore cannot be conveniently and economically preset. Furthermore, this type of system is especially sensitive to electrically inductive signals, so that it is desirable to avoid the use of large solenoids to provide the driving force.

Accordingly, it is an object of the present invention to provide an improved intermittent drive mechanism which overcomes the foregoing difliculties of prior art devices.

Another object of this invention is to provide intermittent drive mechanisms which may be actuated using a minimum of power.

Still another object of this invention is to provide an intermittent drive mechanism of simple, economical design, having long life and enhanced reliability.

Summary of the invention According to one aspect of the invention, a continuously rotating shaft has mounted thereon a driving hub. The intermittently driven member is positioned adjacent the driving hub and includes a driving surface having at least one detent. When the detent is adjacent to the driving hub, the hub does not make contact with the surface of the driven member which remains stationary. A drive tip is mounted loosely on the rotating shaft and is held in a fixed position by an escapement member. When the escapement member releases the drive tip, the rotational motion of the drive shaft moves the drive tip into the detent area between the driven member and the drive shaft. By means of a wedging action, energy from the rotating shaft is coupled through the drive tip to the driven member, thereby inducing the driving surface of the driven member into contact with the drive shaft and imparting the desired motion to the driven member. The driven member continues in motion until the next detent on its driving surface is adjacent to the drive shaft at which time the driven members stop since there is again no contact between the drive shaft and the driven member.

Description of the drawings FIG. 1 is a perspective view of one embodiment of an intermittent drive system incorporating the present invention;

FIGS. 2 and 3 are sequential plan views of the intermittent drive mechanism of FIG. 1 during a cycle of operation;

FIG. 4 is a sectional view of the driving tip and driving hub taken along lines 4-4 of FIG. 3; and

FIG. 5 is a plan view of an alternate embodiment of an intermittent drive mechanism according to the present invention.

Description of the preferred embodiments For a better understanding of the present invention, together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the above-described drawings.

Referring now to FIG. 1, there is shown a drive system including a motor 11 having a shaft 13 attached to a pulley 15. A drive belt 17 is connected between the motor pulley 15 and a second pulley 19. A drive shaft 21 is affixed to the pulley 19 and extends through the mounting surface 23 of the system incorporating the drive mechanism. Mounted on and secured to the drive shaft 21 is a driving hub 25, and mounted loosely above the driving hub on the drive shaft is a driving tip 27. The driving tip has two protuberances 29 and 31 extending therefrom. The second protuberance 31 extends outward and down parallel to the axis of the drive shaft 21 and driving hub 25. An escapement member 33 including a movable plate 35 3 has attached thereto first and second arms 37, 39 which extend outward to be disposed on opposite side of the driving tip 27. The first arm 37 of the escapement member is formed as shown to provide positive engagement with the first protuberance 29 of the driving tip 27.

Disposed adjacent to the drive shaft 21 proximate the driving hub 25 is the member 41 to be intermittently driven. This driven member 4.1 is secured to a shaft 43 which extends upward through the mounting surface 23. The device (not shown) to be intermittently driven may be suitably attached to the upper portion 45 of the shaft 43. The driven member 41 includes a driving surface 47 with a portion of the member formed to provide a detent 49 in the driving surface. As illustrated in FIG. 1, the detent 49 is disposed adjacent the driving hub 25 so there is no contact between the hub and the driving surface of the driven member. Also, the escapement member 33 is positioned such that the first arm 37 thereof is in positive engagement with the driving tip 27. Therefore, even though the drive shaft is rotating as indicated by the direction of the arrows, the driving tip is held stationary by the arm 37 of the escapement member 33.

Referring next to FIG. 2, to initiate the intermittent driving motion of the driven member 41, the escapement member is moved from the first holding position as indicated by the shadowed lines to a second position as illustrated, where the first protuberance 29 of the driving tip 27 is released from the restraint of the arm 37. The movement of the escapement member may be accomplished in any of a number of ways depending upon particular design considerations or preferences. For example, the escapement member could be controlled by a relay activated mechanism or could be manually operated. The coupling between the drive shaft 21 and the driving tip 27 causes the driving tip to rotate with the shaft, rotating the protuberance 31 of the driving tip into the detent 49 in the driving surface 47 of the driven member 41. As the protuberance 31 of the driving tip enters the detent 49, since the protuberance 31 as illustrated is at least as wide as the opening between the driven member 41 and the driving hub 25, the protuberance provides a direct coupling between the driven member 41 and the driving hub 25 and a wedging action occurs to provide a coupling between the driving hub 25 and the driven member 41, thereby initiating rotational motion of the driven member in a clockwise direction as illustrated.

As the driving tip passes out of the detent 49, the driving hub 25 comes into intimate contact with the driving surface 47 of the driven member 41 as illustrated in FIG. 3. This contact continues the rotational motion of the driven member 41 until the detent 49 once again becomes adjacent the driving hub 25 as shown in FIG. 1, thereby breaking the contact between the hub and the driving surface 47 of the driven member 41.

The following action precludes the possibility of initiating more than one drive cycle each time the escapement member is moved from the first hold position to the second activate position. When the escapement member moves to the second position as shown in FIG. 3, the second arm 39 of the escapement member is moved into position to block the first protuberance 29 of the driving tip 27. The blocking action is maintained until the escapement member 33 is returned to the first hold position as illustrated in FIG. 1 when the driving tip rotates until the protuberance 29 comes into contact with the holding arm 37. Therefore, only one cycle of intermittent drive motion can occur each time the escapement member is moved from the first hold position to the second position and back to the first position.

The sectional view of FIG. 4 illustrates the relative spacing between the protuberance 31 of the driving tip 27 when the driving tip is held stationary by the arm 37 of the escapement member 33. As shown there is a small gap between the protuberance 31 and hub 25 to avoid frictional contact therebetween in the hold position. Also,

the drawing of FIG. 4 is somewhat exaggerated to show a spacing 53 representing the aforementioned loose coupling between the drive shaft 21 and the driving tip 27. Because of this loose coupling, a minimal force is required to hold the driving tip stationary and also a minimal force is required to actuate the escapement member to effect the release of the driving tip and initiation of the intermittent drive cycle.

FIG. 5 illustrates an alternate embodiment of the invention where the driven member is a bar 61 positioned within guide channels 63, 65. The driving surface 67 of the bar contains a plurality of detents 73, 75, 77 and 79, and as illustrated these detents do not have to be equally spaced. The intermittent drive means are the same as those described in FIG. 1 and include the rotating drive shaft 21, the driving hub 25 and the drive tip 27 including protuberances 29 and 31. Only one arm 81 of an escapement member is shown although it is readily apparent that the escapement member 33 of FIG. 1 could be utilized with this embodiment. According to this embodiment, the rotational motion of the drive shaft is intermittently translated into linear motion of the bar 61. As illustrated, upon release by the escapement member 81, the protuberance 31 of the driving tip 27 is rotated into the detent 73 and by the above-described wedging action provides driving contact between the driving hub 25 and the bar 61, initiating a sliding motion of the bar 61 in the direction indicated. As the protuberance passes from the detent 73, the driving hub 25 comes in direct contact with the driving surface 67 of the bar 61 and continues to drive the bar until the next detent 75 comes into position adjacent to the driving hub, thereby breaking the driving contact.

In the embodiments of the invention shown in FIGS. 1-3, it will be readily apparent that the driven member may take many other forms. For example, the driving surface 47 may contain a plurality of detents therein, similar to the bar 61 of FIG. 5 such that each intermittent drive cycle rotates the driven member 41 less than a full revolution. Also, rather than attach the device to be intermittently driven to the end 45 of the shaft 43, the face 42 of the member 41 may be a cammed surface with a follower arm resting thereon being driven during each intermittent drive cycle. In some applications it is found desirable to make the driving tip 27, the driving hub 25 or the driving surface 41 of material having a degree of resiliency to permit some compression of the members while avoiding the possibility of jamming the drive mechanism.

It is also recognized that the drive tip and the detents in the driven member may assume a wide range of shapes and sizes so long as they co-act to provide the necessary wedging action, necessary to initiate the intermittent drive motion. Although the preferred embodiments suggest the use of a separate driving hub secured to the rotating shaft, it is noted that a portion of the drive shaft could be the driving hub, that is, the drive shaft would come into direct contact with the driving surface of the driven member to impart the intermittent drive motion. Other modifications and variations will be readily recognized by those skilled in the art to conform to system requirements or design preferences.

It is thus apparent that applicants have provided an improved drive mechanism for imparting intermittent drive motion to a driven member. The mechanism requires a minimum of power for actuation and is of relatively simple, economical design. The mechanism is highly reliable, in one case having surpassed one hundred thousand cycles of operation without any significant degradation of system performance.

While there have been shown and described what are at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various other changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.

We claim:

1. An intermittent drive mechanism comprising:

driving means including a rotating element;

a driving hub portion related to said rotating element;

a driven member having a driving surface including at least one detent in said driving surface;

means positioning said driven member adjacent said driving hub such that the driving surface of said driven member when proximate said driving hub is normally in contact therewith but when said detent in driving surface of said driven member is proximate said driving hub, there is no contact between said driven member and said driving hub;

a drive tip mounted loosely on said rotating element;

an escapement device positioned relative to said drive tip, operative to hold said drive tip stationary; and means releasing said drive tip from said escapement member, whereby said drive tip is rotated on said rotating element to enter the detent in the driving surface of said driven member thereby imparting motion to said driven member to bring the driving surface of said driven member into contact with said driving hub.

2. The invention according to claim 1 wherein said driven member is a rotatable cam having at least one detent in its driving surface.

3. The invention according to claim 1 wherein said driven member is a slidable bar having a plurality of detents in its driving surface.

4. The invention according to claim 1 wherein said driven member is a rotatable cam having a plurality of detents in its driving surface each of said detents corresponding to a predetermined cam position, whereby said cam is driven from one position to the next adjacent position each time said drive tip is released from said escapement member.

5. The invention according to claim 1 wherein said driven member is a rotatable cam having one detent in its driving surface whereby said cam makes one complete revolution each time said drive tip is released from said escapement member.

6. The invention according to claim 1 wherein said escapement member comprises:

a plate capable of assuming one of two predetermlned positions; and

first and second retaining arms secured to said plate,

extending thereform to opposite sides of said rotating element adjacent to said drive tip, said first arm shaped to hold said drive tip stationary when the plate is in a first position, and said second arm shaped to prevent said drive tip from making more than one revolution when the plate is in the second of the two positions.

7. The invention according to claim 1 wherein said driving hub portion related to said rotating element comprises a cylindrical piece of resilient material channeled along the cylindrical axis thereof, and further includes means for mounting and securing said driving hub to said rotating hub.

8. The invention according to claim 1 wherein said driving tip comprises a piece of resilient material channeled along an axis and adapted to be mounted on said rotating element, said piece of resilient material including first and second protuberances extending therefrom, said first protuberance being normal to said channeled axis and said second protuberance being normal to said channeled axis and including a portion extending in a direction parallel to said channeled axis.

9. The invention according to claim 8 wherein said escapement member comprises:

a plate capable of assuming one of two predetermined positions; and

first and second retaining arms secured to said plate,

extending the refrom to opposite sides of said rotating element adjacent to said drive tip, said first arm shaped to hold said drive tip stationary when the plate is in a first position by positively engaging and restraining said first protuberance and said second arm shaped to prevent said drive tip from making more than one revolution when the plate is in the second of the two positions by blocking said first protuberance.

10. The invention according to claim 9 wherein the means releasing said drive tip from said escapement member comprises means moving said plate from said first assumable position to said second assumable position.

References Cited UNITED STATES PATENTS 3,223,205 12/1965 McCurdy 74112 2,554,981 5/1951 Golf 7484 FOREIGN PATENTS 419,283 3/1947 Italy.

FRED C. MATTERN, 111., Primary Examiner. W. S. RATLIFF, JR., Assistant Examiner.

@22 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,446,086 Dated 5/27/69 Inventor(s) John Robert Peltz and Clayton L- Stnldt' It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 40 of the specification "has found" should read--which has found--.

Column 4, line 46 of the specification "surface 41" should read-surface 47--.

Column 5, line 12 of the claims (claim 1) "in driving" should read--in the driving--.

Column 6, line 26 of the claims (claim 9) "the refrom" should read--therefrom--.

SIGNED AND SEALED IAR 3 4970 (SEAL) Amen Edward M. member, In

WILLIAM E. suuuym, .m. A g Officer Oounissioner 0! Patents I... r I .J 

